The goal of the present work is to study the structure and biosynthesis of human histocompatibility antigens (HL-A). Two types of material will be used in these structural studies. First, the histocompatibility antigens will be solubilized for several cultured human lymphoblastoid lines with papain. These materials will then be purified. Finally, attempts will be made to separate molecules containing the various HL-A specificities so that structural studies can be carried out on them. Similar studies with detergent solubilized HL-A antigens are in progress. The role of dolichyl phosphate derivatives in the biosynthesis of glycoproteins using human lumphocyte preparations is being investigated. This phospholipid serves as a carrier of activated sugar fragments for utilization for various synthetic processes. These derivatives are presumably involved in the biosynthesis of the glycan moieties of HL-A antigens and other glycoproteins.